Abstract:

The appearance, physiological and biochemical differences among normal juice sacs, granulating juice sacs and
granulated juice sacs of red-fleshed sweet pomelo (Citrus grandis) were investigated in this study. The results showed that
the contents of dry matter and total sugars, titratable acid, vitamin C, red pigments and total phenolic in granulated juice
sacs gradually decreased with the extent of granulation. The fresh weight and the contents of reducing sugar and protein
first increased and then declined, which lowered the nutritional quality of juice sacs. The enzymes activities of superoxide
dismutase (SOD), peroxidase (POD), and catalase (CAT) changed disorderly and polyphenoloxidase (PPO) activity
significantly decreased, resulting in an increase in malondialdehyde (MDA) content and lignin synthesis, which finally
caused granulation of juice sacs of red-fleshed sweet pomelo.

Key words: red-fleshed sweet pomelo, juice sac, granulation, quality, activity of oxidase